The primary objectives of the Animal Handling and Imaging Core are five-fold: 1) To purchase, create, or acquire mouse genetic models required for the program project and to maintain those to be used by two or more projects ("CORE" mice) under a controlled breeding program. 2) To provide CORE mice to investigators for completion of project-specific experiments upon request. 3) To provide state-of-the-art facilities and technical support for, and expertise in, mammary-specific and general surgical procedures. 4) To serve as a center for coordination of tissue sharing among PPG investigators. 5) To provide imaging capabilities for evaluation of tumor development and metastasis in living mice. In addition, this Core will be responsible for all per diem cage costs related to the program project. Because space in the animal facility is finite, each project has been allocated a certain number of cages that can be maintained on average at any given time. Finally, the Animal Handling Core will provide a database of all mice generated by the project and documentation related to tissue samples, gene expression profiles, and histological evaluation. The data entry and database format will be based on our existing software for our extensive human tissue banks. Tissue sharing and animal space coordination among the Projects will result in specific cost savings, in addition to the enhanced effectiveness of shared expertise and facilities such as the imaging equipment. The Animal Handling and Imaging Core is required by all five Projects in the Program Project.